A schematic block diagram of a conventional control unit is shown in FIG. 7. As shown in FIG. 7, in this control unit, reference numeral 1 denotes a keyboard for inputting data, 2 denotes a mouse for choosing a button on the screen, 3 denotes a processing unit for controlling each processing, 4 denotes a CRT which displays data, 5 denotes an error message display unit and 6 denotes an error contents detailed display unit.
The conventional control unit operates as follows. The control unit displays the error display screen 7 shown in FIG. 8. If an error occurs in a machine to be controlled, for example, in a machine tool such as a laser beam machine, a primary error message corresponding to this error is displayed on an error number/name display section 8, and detailed contents of the error are displayed in an error contents display section 9.
The primary error message, for example, may be a combination of an error number and an error name, determined in advance, corresponding to each error.
Moreover, when a plurality of errors occurs simultaneously, respective primary error messages, that is, the error numbers and the error names are displayed in a plurality of lines at the same time on the error number/name display section 8.
Thus, in case of the conventional control unit, when an error occurs, the error number and name, and detailed contents of the error stored beforehand corresponding to this error number are displayed. However, there are no means in the conventional control unit for an individual user to add and record peculiar error information, for example, an error corrective action or the like and display it again. Therefore, the user has to note the user specific error corrective action or the like on a sheet of paper, corresponding to the error, which is inconvenient. Moreover, a figure or an explanatory note is used as detailed description of errors, but there may be only an explanatory note without a figure, depending on the error. In this case, the size which displays the explanatory note is fixed, regardless of there being a figure or not, and in the case of displaying in a limited screen size, detailed contents cannot be displayed. Also, when a plurality of errors occurs at the same time, there is no mechanism for the user to select the error details.
The present invention has been made in order to solve the above-described problems. It is an object of the present invention to obtain a control unit that can correspond to various types of users, wherein at the time of occurrence of error, each user can deal with the error quickly and properly.